Abstract: In a digital Time Division Multiple Access radio communications network that includes a number of Base Transceiver Stations, and several Mobile Stations, a handover can be accomplished so that the parameters required in identifying a Mobile Station, and the frequency data, the data of the time interval to be used, as well as the frame number data of the channel are given to a new Base Transceiver Station to which a Mobile Station will be moved. The new Base Transceiver Station is tuned to listen to the channel determined by the data it received. The former Base Station transmits a handover command to the Mobile Station containing the frequency data, the data of the time interval to be used, as well as the frame number data of the channel to which the new Base Station has moved. After the command the Mobile Station turns the trafficing directly to said channel.

Abstract: An antenna rod, comprises an antenna lead passing inside the rod and a layer of polymer material outside the antenna lead. The antenna rod has improved characteristic features because the antenna lead has been immersed into the polymer material layer. The antenna rod is produced by inserting the antenna lead longitudinally in a cavity of a casting mold, which is substantially of the shape of the antenna rod and thereafter encapsulating the antenna lead with a polymer material layer. The antenna lead can be reinforced for casting by joining it with a support structure by winding the lead to form a helical coil around the support structure.

Abstract: In the method of tuning the received signal strength indicator the tuning results for selected operating conditions are stored in the microprocessor (10) memory. When the radio telephone (1) is in use, the received signal strength indicator (RSSI) reading is corrected with the tuning result in order to select the strongest antenna signal. The tuning is performed by connecting the tuning equipment (2)to the external interfaces (31, 32) of the radio telephone without opening it.

Abstract: The present invention relates to a circuit arrangement by which a voltage-controlled temperature-compensated oscillator (VCTCXO) (10) serving as the frequency reference in a radio telephone is controlled. In the circuit arrangement there is used a phase-locked loop which locks the frequency of the VCTCXO (10) to the frequency of the intermediate-frequency signal (2.IF) of the receiver of the telephone. When the telephone is started up, a constant setting voltage (30) is coupled as the control signal (V.sub.con) for the VCTXCO (10) for controlling the reference frequency. In the call state the control signal (V.sub.con) is provided by by the phase-locked loop in which the locking is to the frequency of the intermediate frequency signal. When the call is cut off the control voltage (V.sub.con) is supplied from a memory (26) coupled to the phase-locked loop in which the value of the control signal (V.sub.con) is substantially equal to the control signal (V.sub.

Abstract: A converter system is comprised of an analog-to-digital converter (1) and a digital-to-analog converter (2). A first base number of a number system used in the analog-to-digital converter is less than 2, and a second base number of a number system used in the digital-to-analog converter is less than two. The first base number does not equal the second base number. For example, both are within a range from 1.90 to 1.99. In a calibration method the output of the digital-to-analog converter is switched to the input of the analog-to-digital converter, and a controller (3) provides digital values to the input of the digital-to-analog converter, and receives corresponding digital values from the output of the analog-to-digital converter.

Abstract: In a radio-telephone system based on time-division multiple access, the AGC function of the receiver can be controlled so as to be approximating the actual value at the beginning of the reception timeslot. The field strength of a specific signal transmitted by a base station during a timeslot preceding a concerned reception timeslot is measured, the specific signal having a power the ratio of which to the power of the concerned signal is presumed. On the basis of this measured field strength and the presumed ratio, the required AGC gain of the AGC amplifiers is calculated and the AGC gain is set according to the calculated gain for the time of the concerned reception timeslot.

Abstract: An integrated dynamic amplitude limiter is disclosed for limiting the deviation of a transmitter operating at audio frequencies. In an amplitude limiter according to the invention, a dynamic AGC amplifier block (1), a level clipper block (3) and a block (2) which forms the higher and lower limiting levels are implemented using switched capacitors (SC), and they are formed into an integrated amplitude limiter circuitry, and the voltages which define the higher and lower limiting levels are formed from the voltage of the band-gap voltage reference (Vbgref), which voltage is formed in relation to the virtual ground voltage of the amplifier circuitry, in which case the limiting levels are independent of the supply voltage (Vdd).

Abstract: The efficiency of a Viterbi algorithm in a communication system, in which the transmission channel contains memory, is improved when several sequences in a signal string are detected in descending probability order. An error detecting operation then selects the correct sequence, if any, to be the received sequence.

Abstract: Speech coding of the code excited linear predictive type is implemented by providing an excitation vector which comprises a set of a pre-determined number of pulse patterns from a codebook of P pulse patterns, which have a selected orientation and a pre-determined delay with respect to the starting point of the excitation vector. This requires modest computational power and a small memory space, which allows it to be implemented in one signal processor.

Abstract: The invention relates to a method, in which a phase modulated or frequency modulated signal can be directly generated with a PLL frequency synthesizer. With an interpolating synthesizer it is possible to create a very dense output frequency (f.sub.x) raster, so that the pulses received in the phase comparator (63) both from the reference signal (f.sub.o) branch and from the voltage controlled oscillator VCO (65) are lengthened in lengthening means (62, 69; 67, 68; k.sub.1, L+.DELTA.L; k.sub.2, L) by a desired amount. The numbers k.sub.1 and k.sub.2 are proportional to the amount of lengthening. When these integers now further are changed proportionally to the modulating signal, the change of the integers causes a change of the time difference of the pulses received by the phase comparator (63). This change of the time difference further causes a change in the output signal (f.sub.x) of the voltage controlled oscillator.

Abstract: A method for use in a digital data transfer apparatus, such as a radio telephone (10), that includes an adaptive equalizer, such as an adaptive filter (32), for receiving, correcting, and outputting data symbols. The method determines correction coefficients for the adaptive equalizer and includes a first step of, for every data symbol output by the adaptive equalizer, maintaining a first matrix R that is a NxN channel correlation matrix and a second matrix P that is a N.times.1 cross correlation vector between a received signal and a transmitted symbol. The method includes a second step of, for every k.sup.th symbol output by the adaptive equalizer, determining a set of correction coefficients (C) for the adaptive equalizer based upon the matrices R and P. A third step of the method applies the set of determined correction coefficients to the adaptive equalizer so as to optimally correct a subsequently received data symbol.

Abstract: The channel frequency of a digital radiotelephone is coarse tuned utilizing the phase information of the symbols. According to the invention the phase change between the measured phases of one or more received symbols (d) and the previous symbol (e) is detected, the phase change being compared with allowed phase changes. Based on this a decision (g) is made concerning the phase of the transmitted symbol, the phase error (f.sub.err) or difference between the decision (g) and the measured phase change (d) is generated, and on this basis the channel frequency is adjusted.

Abstract: A phase locked loop system including first and second counters connected respectively to first and second registers. The first register contains a number M and the second register contains a number N. The first counter is responsive to a reference signal Fref and the second counter is responsive to an output signal Fout. The first counter provides an output signal F1 responsive to M cycles of Fref and the second counter provides an output signal F2 responsive to N cycles of Fout. The F1, F2, Fref and Fout signals are connected to a phase detection circuit where the phases of Fref and Fout are compared under the control of the larger states of F1 and F2. The output signal of the phase detection circuit is connected to a voltage controlled oscillator that produces the output signal Fout proportional to the phase detection circuit output signal. The Fout signal is looped back to the second counter until the phase locked loop system settles when Fref/M equals Fout/N.

Abstract: A phase detector for high speed logic circuits including an edge detector circuit responsive to two signals which may contain frequency and phase errors which result in the edges of the signal pulses of the two signals occurring at different times. The edges of the two signal pulses are detected by a phase detector circuit and an output signal provided to a correction circuit that provides a correction signal for the time period between the pulse edges of the signal pulses. The correction circuit output signal is fed back to a local oscillator to minimize the frequency and phase errors. A synchronizing circuit is connected to the output of the correction circuit to synchronously reset the phase detector circuit at the end of the correction signal period.

Abstract: In the method according to the invention, the initialization data of a mobile telephone are installed directly in the rapid dialing memory or by using the rapid dialing memory, in which case the installation program transfers to the nonvolatile memory the data fed from the mobile telephone keyboard to the rapid dialing memory.